1. Field of the Invention
The present invention relates to a grid interconnection device and a power control system configured to control a backward flow power toward a power distribution system.
2. Description of the Related Art
Nowadays, there have been increasing cases where a power supply device and a power storage device are provided in a customer (for example, a house and a factory) supplied with alternating current power from a substation. Specifically, plural power distribution systems are provided under the management of the substation, and the power supply device and the power storage device are connected to one of the power distribution systems through a grid interconnection device. Electric power supplied from the power supply device is not only supplied to power consumption devices such as a household electric appliance provided in its own customer, but also may be provided to the power distribution system as a backward flow through the grid interconnection device.
Here, if consumed power of the power consumption devices installed in each of customers reaches a peak as in the case of the afternoon in summer, for example, the consumed power in each customer may exceed the electric power supplied from the substation.
To address this problem, there has been proposed a technique for providing, within an acceptable range, the backward flow of the electric power supply from the power supply device in each customer in accordance with an instruction from the substation (see Japanese Patent Application Publication No. Hei 10-248180).